Clare Kennedy, a niece of RTE presenter Mary Kennedy, said Ciaran's death had left them heartbroken.
Ciaran (25) was swept to his death in the River Liffey at the Ballysmuttan Bridge near his home in Manor Kilbride, Co Wicklow, as he came to the aid of motorists during torrential rain.
His body was found on Tuesday morning some 4km downstream from where he entered the water.
Ciaran's mother and father Brenda and John, brother Alan and sister Michelle, as well as his girlfriend Clare were the chief mourners yesterday.
Taoiseach Enda Kenny and Justice Minister Alan Shatter also attended the packed funeral Mass at St Brigid's Church in Ciaran's home village.
Also there to pay their respects was Garda Commissioner Martin Callinan as well as many of the force's top officials, the President's representative Commandant Michael Walsh, and Brian Purcell, the Secretary General of the Department of Justice.
In a moving tribute to Garda Jones, an inter county Gaelic football star for Wicklow, the deceased's girlfriend Ms Kennedy told mourners of "the pride of Kilbride".
Addressing the packed church, she said she maintained a diary as a schoolgirl and told how on Thursday night she had gone through her writings to try to find something to say.
Fighting back her emotions, she read a passage from February 28, 2003, when the then schoolgirl had recorded how Ciaran -- "the untouchable 5th year" -- had begun sending text messages to her.
"News of the century...I think he likes me," the diary entry ended, she said.
"Months later Ciaran told me he was going to phone me for the first time and I had written down a list of topics for a conversation should we run out of things to talk about, but we didn't need them, we were never stuck for words.
"Now I would write 'thank you for the last eight years... I loved you...and I will continue to love you'."
She added: "Our hearts are broken but I have no doubt he will continue to protect us...he was the pride of Kilbride."
Garda Jones was buried in the adjoining cemetery with full garda honours.